The TrayCell fiber optic microliter cell from Hellma GmbH & Co. KG is designed for applications such as protein and nucleic acid analysis, determining the incorporation frequency of fluorescent dye labels, and UV and VIS analysis over the wavelength range of 190 to 1100 nm. It accurately analyzes extremely small samples with suitable reproducibility. The 12.5 × 12.5-mm dimensions of the cell are equivalent to a standard cuvette to work in most spectrophotometers. The 1- and 0.2-mm caps create a defined optical light path of 1 and 0.2 mm, respectively. This capability generates virtual dilution factors of 1:10 or 1:50, compared with measurement with a 10-mm cuvette, saving time and reducing dilution errors. The required sample volume for the 1-mm cap is 3 to 5 μl and for the 0.2-mm cap, 0.7 to 4 μl. Available in two heights, the cells can remain in the photometer during filling and cleaning stages.